fixed BooleanLiteral value

[ktb88]

This PR fixed to correct value of BooleanLiteral.

The original code compared with True so that true value produced false value.

pragma solidity 0.5.11;
contract C {
  function f() public {
    bool a = true;
  }
}

"type": "VariableDeclarationStatement",
"variables": [
    {
        "type": "VariableDeclaration",
        "typeName": {
            "type": "ElementaryTypeName",
            "name": "bool",
            "loc": {
                "start": {
                    "line": 4,
                    "column": 4
                },
                "end": {
                    "line": 4,
                    "column": 4
                }
            }
        },
        "name": "a",
        "storageLocation": null,
        "loc": {
            "start": {
                "line": 4,
                "column": 4
            },
            "end": {
                "line": 4,
                "column": 9
            }
        }
    }
],
"initialValue": {
    "type": "BooleanLiteral",
    "value": false,
    "loc": {
        "start": {
            "line": 4,
            "column": 13
        },
        "end": {
            "line": 4,
            "column": 13
        }
    }
},

[tintinweb]

oh, good catch @ktb88! 🙌

thanks for the fix!
cheers,
tin